Semiconductor device

ABSTRACT

A semiconductor device is provided with a semiconductor element, a main lead on which the semiconductor element is disposed, and a resin package that covers the semiconductor element and the main lead. A notch that is recessed toward the center of the main lead in plan view as seen in the thickness direction of the semiconductor element is formed in the main lead.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device.

2. Description of Related Art

Heretofore, semiconductor devices in which semiconductor elements suchas transistors are sealed by a resin package, for example, have beenproposed. Among such semiconductor devices, a semiconductor deviceprovided with a semiconductor element having three electrodes, threeleads electrically connected to these electrodes, and a resin packagecovering the semiconductor element and a portion of each of the threeleads, for example, has been disclosed. The three electrodes are formedon the same surface of the semiconductor element. The semiconductorelement is joined to one of the three leads. The three electrodes arerespectively electrically connected to a different one of the threeleads via three wires. The resin package covers the entirety of thesemiconductor device, all of the three wires, and a portion of each ofthe three leads. Portions of the three leads that project from the resinpackage serve as terminal areas for mounting the semiconductor device.Known documents relating to semiconductor devices includeJP-A-2012-190936, for example.

In a conventional semiconductor device, the semiconductor element may besmaller in plan view than the lead on which the semiconductor element isdisposed. Thus, depending on the technician, the semiconductor elementcould possibly be displaced from the desired disposition location on thelead.

SUMMARY OF THE INVENTION

The present invention has been proposed under the above circumstances,and a main object of the invention is to provide a semiconductor devicethat enables a semiconductor element to be disposed at a desiredlocation on the lead, irrespective of the technician, even in the casewhere the semiconductor element is comparatively small.

According to an aspect of the present invention, a semiconductor deviceis provided that includes a semiconductor element, a main lead on whichthe semiconductor element is disposed, and a resin package covering thesemiconductor element and the main lead, with a notch recessed toward acenter of the main lead in plan view as seen in a thickness direction ofthe semiconductor element being formed in the main lead.

Preferably, the semiconductor device further includes a first auxiliarylead electrically connected to the semiconductor element, and the firstauxiliary lead is separated from the main lead and exposed from theresin package.

Preferably, the notch has a shape recessed in a direction from the firstauxiliary lead toward the main lead in plan view.

Preferably, the main lead has an end face located furthest on the firstauxiliary lead side of the main lead, and the notch has a shape recessedfrom the end face in plan view.

Preferably, the notch has a shape recessed from a region on an oppositeside of the main lead to the first auxiliary lead in plan view.

Preferably, the main lead has an end face located on the opposite sideof the main lead to the first auxiliary lead, and the notch has a shaperecessed from the end face in plan view.

Preferably, the main lead has a main lead main surface and a main leadback surface that face in opposite directions to each other, and thesemiconductor element is disposed on the main lead main surface.

Preferably, the main lead includes a main full thickness part and a maineave part, the main full thickness part extends from the main lead mainsurface to the main lead back surface, and the main eave part projectsfrom the main full thickness part in a direction at right angles to thethickness direction of the semiconductor element.

Preferably, the semiconductor element overlaps with each of the mainfull thickness part and the main eave part in plan view.

Preferably, the notch is formed in the main eave part.

Preferably, the semiconductor element overlaps with the main lead inplan view, throughout an entirety of the semiconductor element.

Preferably, the main eave part has a main front part, the main frontpart projects from the main full thickness part toward the firstauxiliary lead, and the notch is formed in the main front part.

Preferably, the main eave part has a main lateral part, and the mainlateral part projects from the main full thickness part in a directionat right angles to the direction in which the main front part projects.

Preferably, the main lead includes a first main lateral connecting partprojecting from the main eave part, the direction in which the firstmain lateral connecting part projects is a direction orthogonal to adirection from the main lead toward the first auxiliary lead, and thefirst main lateral connecting part has an end face exposed from theresin package.

Preferably, the main lead includes a second main lateral connecting partprojecting from the main eave part, the direction in which the secondmain lateral connecting part projects is a direction orthogonal to adirection from the main lead toward the first auxiliary lead, the secondmain lateral connecting part has an end face exposed from the resinpackage, and the first main lateral connecting part and the second mainlateral connecting part are juxtaposed with each other.

Preferably, the second main lateral connecting part is located betweenthe first main lateral connecting part and the first auxiliary lead in adirection from the main lead toward the first auxiliary lead.

Preferably, a distance separating the first main lateral connecting partfrom the second main lateral connecting part is 0.2 to 0.3 mm.

Preferably, the main eave part has a main rear part, and the main rearpart projects from the main full thickness part in an opposite directionto the direction in which the main front part projects.

Preferably, the main lead includes a main rear connecting partprojecting from the main rear part, and the main rear connecting parthas an end face exposed from the resin package.

Preferably, the main full thickness part is surrounded by the main eavepart in plan view, throughout an entirety thereof.

Preferably, the semiconductor device further includes a main frontsurface plating layer formed on the main lead, and interposed betweenthe semiconductor element and the main lead.

Preferably, the main front surface plating layer has a substantiallyrectangular shape in plan view.

Preferably, the notch has a shape in which the main front surfaceplating layer is recessed in plan view.

Preferably, the main front surface plating layer overlaps with anentirety of the main eave part.

Preferably, the first auxiliary lead includes a first auxiliary fullthickness part and a first auxiliary eave part, the first auxiliary leadhas a first auxiliary lead main surface and a first auxiliary lead backsurface that face in opposite directions to each other, the firstauxiliary full thickness part extends from the first auxiliary lead mainsurface to the first auxiliary lead back surface, and the firstauxiliary eave part projects from the first auxiliary full thicknesspart in a direction at right angles to the thickness direction of thesemiconductor element, and constitutes the first auxiliary lead mainsurface.

Preferably, the first auxiliary eave part has a first auxiliary frontpart, and the first auxiliary front part projects from the firstauxiliary full thickness part toward the main lead.

Preferably, the first auxiliary lead includes a first auxiliary lateralconnecting part projecting from the first auxiliary eave part, thedirection in which the first auxiliary lateral connecting part projectsis a direction orthogonal to a direction from the main lead toward thefirst auxiliary lead, and the first auxiliary lateral connecting parthas an end face exposed from the resin package.

Preferably, a distance separating the first auxiliary lateral connectingpart from the main lead is 0.2 to 0.3 mm.

Preferably, the semiconductor device further includes a first wirejoined to the semiconductor element, and electrically connecting thesemiconductor element and the first auxiliary lead.

Preferably, the semiconductor device further includes a first auxiliarysurface plating layer interposed between the first auxiliary lead andthe first wire.

Preferably, the semiconductor device further includes a second auxiliarylead that is electrically connected to the semiconductor element, andthe second auxiliary lead is separated from the main lead and exposedfrom the resin package.

Preferably, the semiconductor device further includes a second wirejoined to the semiconductor element, and electrically connecting thesemiconductor element and the second auxiliary lead.

Preferably, the semiconductor device further includes a second auxiliarysurface plating layer interposed between the second auxiliary lead andthe second wire.

Preferably, the semiconductor element has a semiconductor layer, aeutectic layer of a semiconductor and a metal, and a monolithic metallayer constituting a back surface electrode that are laminated one onthe other, and the monolithic metal layer is joined directly to the mainlead.

Preferably, the eutectic layer is made of a eutectic of Si and Au.

Preferably, the monolithic metal layer is thinner than the eutecticlayer.

Further features and advantages of the present invention will becomeapparent from the following detailed description with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of a semiconductordevice that is based on a first embodiment of the present invention.

FIG. 2 is a perspective view showing the semiconductor device of FIG. 1.

FIG. 3 is a plan view showing the semiconductor device of FIG. 1.

FIG. 4 is a cross-sectional view along a line IV-IV in FIG. 3.

FIG. 5 is a cross-sectional view along a line V-V in FIG. 3.

FIG. 6 is an enlarged cross-sectional view showing a main section of thesemiconductor device of FIG. 1.

FIG. 7 is a cross-sectional view along a line VII-VII in FIG. 3.

FIG. 8 is a cross-sectional view along a line VIII-VIII in FIG. 3.

FIG. 9 is a cross-sectional view along a line IX-IX in FIG. 3.

FIG. 10 is an enlarged plan view showing a main section of asemiconductor element of the semiconductor device of FIG. 1.

FIG. 11 is an enlarged image showing a second bonding part formed in anexample of a manufacturing process of the semiconductor device of FIG.1.

FIG. 12 is a perspective view showing an example of a semiconductordevice that is based on a second embodiment of the present invention.

FIG. 13 is a plan view showing the semiconductor device of FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be specificallydescribed with reference to the drawings.

First Embodiment

A first embodiment of the present invention will be described usingFIGS. 1 to 11.

FIG. 1 is a perspective view showing an example of a semiconductordevice that is based on the first embodiment of the present invention.FIG. 2 is a perspective view showing the semiconductor device of FIG. 1.FIG. 3 is a plan view showing the semiconductor device of FIG. 1. FIG. 4is a cross-sectional view along a line IV-IV in FIG. 3. FIG. 5 is across-sectional view along a line V-V in FIG. 3. FIG. 6 is an enlargedcross-sectional view showing a main section of the semiconductor deviceof FIG. 1. FIG. 7 is a cross-sectional view along a line VII-VII in FIG.3. FIG. 8 is a cross-sectional view along a line VIII-VIII in FIG. 3.FIG. 9 is a cross-sectional view along a line IX-IX in FIG. 3. FIG. 10is an enlarged plan view showing a main section of the semiconductorelement of the semiconductor device of FIG. 1.

A semiconductor device 101 shown in these diagrams is constituted as aso-called surface mount type semiconductor device that is comparativelycompact. To give an example of the size of the semiconductor device 101,the semiconductor device 101 has dimensions of about 1.0 mm in an xdirection, about 0.6 mm in a y direction, and about 0.36 mm in a zdirection. Note that the z direction is the thickness direction of thesemiconductor element, a main lead, a first auxiliary lead, and a secondauxiliary lead.

The semiconductor device 101 is provided with a semiconductor element200, a main lead 300, and a first auxiliary lead 400, a second auxiliarylead 500, a first wire 600, a second wire 700, and a resin package 800.Note that the z direction is the thickness direction of thesemiconductor element 200, and the view in the z direction is equivalentto a so-called plan view.

The semiconductor element 200 is, in the present embodiment, constitutedas a so-called transistor. The semiconductor element 200 has a frontsurface 201 and a back surface 202, and a first front surface electrode211, a second front surface electrode 212 and a back surface electrode220 are formed thereon. The front surface 201 and the back surface 202face in opposite directions to each other in the z direction. To givenan example of the size of the semiconductor element 200, thesemiconductor element 200 has dimensions of about 300 μm in the xdirection and about 300 μm in the y direction.

As shown in FIGS. 3 and 10, the first front surface electrode 211 andthe second front surface electrode 212 are formed on the front surface201, and are each constituted by a portion of an electrode layer 213consisting of an Au plating layer, for example. In the presentembodiment, the first front surface electrode 211 is a gate electrodeand the second front surface electrode 212 is a source electrode. In thepresent embodiment, the first front surface electrode 211 is located onthe right side in the x direction in FIG. 3, and the second frontsurface electrode 212 is located on the left side in the x direction.Also, the first front surface electrode 211 is located on the lower sidein the y direction in the diagram, and the second front surfaceelectrode 212 is located on the upper side in the y direction. The backsurface electrode 220 (see FIG. 6) is formed on the back surface 202. Inthe present embodiment, the back surface electrode 220 is a drainelectrode.

A portion of the electrode layer 213 has been removed to form a removedregion 214. The removed region 214 is formed into a shape that surroundsthe first front surface electrode 211. More specifically, the removedregion 214 has portions that extend in parallel to each other along thefour sides of the semiconductor element 200, and a portion that ispositioned sandwiching a comparatively large area in order to surroundthe first front surface electrode 211. The first front surface electrode211 and the second front surface electrode 212 are insulated by theremoved region 214 formed into such an annular shape.

The region surrounding the second front surface electrode 212 serves asan active region 216. In the active region 216, a MOSFET 217 is builtinto a region positioned inwardly from the front surface 201 in the zdirection. The MOSFET 217 is constituted by a plurality of unit cells218 disposed in a matrix. Note that the plurality of unit cells 218 arenot limited to being arrayed in a matrix, and may be arrayed in astriped or staggered form, for example.

Note that although, in the present embodiment, one second front surfaceelectrode 212 serving as a source electrode is provided, the presentinvention is not limited thereto and a plurality of second front surfaceelectrodes 212 may be provided.

FIG. 6 shows a vicinity of the back surface electrode 220 of thesemiconductor element 200. The semiconductor element 200 of the presentembodiment has a semiconductor layer 231 and a eutectic layer 232. Thesemiconductor layer 231 is a layer in which each of the regionsfunctioning as a transistor are incorporated, and is made of Si, forexample. The eutectic layer 232 consists of a eutectic mixture of ametal and the semiconductor that constitutes the semiconductor layer231. In the present embodiment, the eutectic layer 232 consists ofeutectic mixture of Au as the metal and Si as the semiconductor. Theeutectic layer 232 is formed by laminating a layer made of Au on thesemiconductor layer 231, and then alloying these materials through theapplication of heat. The back surface electrode 220 is laminated on thelower side of the eutectic layer 232 in the z direction. The backsurface electrode 220 consists of a layer of Au formed by vapordeposition on the eutectic layer 232, for example, and is an example ofwhat is referred to in the present invention as a monolithic metallayer. The eutectic layer 232 has a thickness of about 1200 nm. The backsurface electrode 220 serving as a monolithic metal layer has athickness of about 600 nm, for example, and is thinner than the eutecticlayer 232. In the present embodiment, the surface that faces downwardfrom the eutectic layer 232 in the z direction is defined as the backsurface 202 of the semiconductor element 200.

The main lead 300 has a main lead main surface 310, a main lead backsurface 320, a main full thickness part 330, and a main eave part 340.The main lead 300 is formed by patterning such as etching beingperformed on a metal plate made of Cu, for example. As viewed in thethickness direction z, the semiconductor element 200 overlaps with themain lead 300 throughout the entirety of the semiconductor element 200.

The main lead main surface 310 faces upward in the z direction, and isthe region on which the semiconductor element 200 is mounted. In thepresent embodiment, the main lead main surface 310 has a rectangularshape with dimensions of about 0.4 mm in the x direction and about 0.5mm in the y direction. Also, in the present embodiment, a main frontsurface plating layer 311 is formed on the main lead main surface 310.The main front surface plating layer 311 is interposed between thesemiconductor element 200 and the main lead 300. The main front surfaceplating layer 311 is formed over the entire area of the main lead mainsurface 310. The main front surface plating layer 311 is made of Ag ofabout 2 μm in thickness, for example. Note that, in FIG. 1, the mainfront surface plating layer 311 is shaded for convenience ofunderstanding. In the present embodiment, the main front surface platinglayer 311 is substantially rectangular as seen in the z direction (inplan view).

The main lead back surface 320 faces downward in the z direction in theopposite direction to the main lead main surface 310, and is used inorder to surface mount the semiconductor device 101. The main lead backsurface 320 has a rectangular shape with dimensions of about 0.18 mm inthe x direction and about 0.48 mm in the y direction. The main lead backsurface 320 overlaps with the main lead main surface 310 throughout itsentirety and is contained within the main lead main surface 310, as seenin the z direction (in plan view). In the present embodiment, a mainback surface plating layer 321 is formed on the main lead 300. The mainback surface plating layer 321 is laminated on a region of the main lead300 that is for forming the main lead back surface 320, and is made ofNi, Sn or an alloy thereof at about 0.06 mm in thickness, for example.In the present embodiment, the lower surface of the main back surfaceplating layer 321 in z direction is defined, for convenience, as themain lead back surface 320, although in a configuration that does nothave the main back surface plating layer 321, for example, the main leadback surface 320 may be constituted by the abovementioned portion madeof Cu.

The main full thickness part 330 is a region extending from the mainlead main surface 310 to the main lead back surface 320 in the zdirection. In the present embodiment, the main full thickness part 330indicates a region made of Cu excluding the main back surface platinglayer 321, and the thickness thereof is about 0.1 mm. The main fullthickness part 330 is surrounded around its entirety by the main eavepart 340, as seen in the thickness direction z.

The main eave part 340 projects from a portion on the main lead mainsurface 310 side of the main full thickness part 330 in the x and ydirections, which are at right angles to the z direction. An upper endface of the main eave part 340 in the z direction is flush with the mainfull thickness part 330. In the present embodiment, the main eave part340 has a main front part 341, a main lateral part 342, and a main rearpart 343. The thickness of the main eave part 340 is half of the mainfull thickness part 330, for example.

The main front part 341 projects from the main full thickness part 330toward the first auxiliary lead 400 and the second auxiliary lead 500 inthe x direction.

The main lateral part 342 projects from the main full thickness part 330in the y direction. In the present embodiment, two main lateral parts342 are formed.

In the present embodiment, the main lead 300 has two first main lateralconnecting parts 351A and two second main lateral connecting parts 351B.The first main lateral connecting parts 351A and the second main lateralconnecting parts 351B extend from the main lateral parts 342 of the maineave part 340. The direction in which the first main lateral connectingparts 351A project and the direction in which the second main lateralconnecting parts 351B project is a direction (y direction) that isorthogonal to the direction (x direction) from the main lead 300 towardthe first auxiliary lead 400. The first main lateral connecting parts351A and the second main lateral connecting parts 351B are juxtaposedwith each other. The first main lateral connecting parts 351A and thesecond main lateral connecting parts 351B are formed to have the samethickness as the main lateral parts 342. The first main lateralconnecting parts 351A and the second main lateral connecting parts 351Bhave end faces that are exposed from the resin package 800. The secondmain lateral connecting parts 351B are located between the first mainlateral connecting parts 351A and the first auxiliary lead 400 in thedirection from the main lead 300 toward the first auxiliary lead 400. Adistance L1 (see FIG. 3) separating the first main lateral connectingparts 351A from the second main lateral connecting parts 351B is 0.2 to0.3 mm, for example.

The main rear part 343 projects from the main full thickness part 330 inthe opposite direction to the main front part 341. In the presentembodiment, the main lead 300 has two main rear connecting parts 352.The main rear connecting parts 352 extend from the main rear part 343 ofthe main eave part 340, and are formed to have the same thickness as themain rear part 343. An end face of the main rear connecting parts 352 inthe x direction is exposed from the resin package 800.

According to the abovementioned configuration, in the presentembodiment, all of the main full thickness part 330 is surrounded by themain eave part 340 as seen in the z direction (in plan view). Also,upper surfaces of the main full thickness part 330 and the main eavepart 340 in the z direction form the main lead main surface 310, and themain front surface plating layer 311 overlaps with all of the main fullthickness part 330 and main eave part 340. The semiconductor element 200overlaps with each of the main full thickness part 330 and the main eavepart 340, as seen in the thickness direction z of the semiconductorelement 200.

In the present embodiment, a notch 380 is formed in the main lead 300.The notch 380 has a shape that is recessed toward the center of the mainlead 300 as seen in the thickness direction z of the semiconductorelement 200. Specifically, the notch 380 has a shape that is recessed ina direction from the first auxiliary lead 400 toward the main lead 300,as seen in the thickness direction z of the semiconductor element 200.The notch 380 is formed in the main eave part 340 (more specifically, inthe main front part 341). Also, the notch 380 has a shape formed byrecessing the main front surface plating layer 311 as seen in the zdirection (in plan view).

As shown in FIGS. 1, 3 and the like, the main lead 300 has an end face390 that is located furthest on the first auxiliary lead 400 side of themain lead 300. The end face 390 is constituted by the second mainlateral connecting parts 351B and the main front part 341. Theabovementioned notch 380 has a shape that is recessed from the end face390, as seen in the thickness direction z of the semiconductor element200.

As shown in FIG. 6, the semiconductor element 200 is joined at the backsurface electrode 220 to the main lead main surface 310 (main frontsurface plating layer 311). Specifically, the back surface electrode 220serving as a monolithic metal layer is joined directly to the main leadmain surface 310 (the main front surface plating layer 311) by athermocompression bonding technique. In this thermocompression bonding,only heat and pressure are applied, and vibration is not applied.

The first auxiliary lead 400 is disposed so as to be separated from themain lead 300 in the x direction. The first auxiliary lead 400 isexposed from the resin package 800 to the outside of the resin package800 as seen in the thickness direction z of the semiconductor element200. The first auxiliary lead 400 has a first auxiliary lead mainsurface 410, a first auxiliary lead back surface 420, a first auxiliaryfull thickness part 430, and a first auxiliary eave part 440. The firstauxiliary lead 400 is formed by performing patterning such as etching ona metal plate made of Cu, for example. The first auxiliary lead 400 iselectrically connected to the semiconductor element 200.

The first auxiliary lead main surface 410 faces upward in the zdirection, and is the region to which the first wire 600 is bonded. Inthe present embodiment, the first auxiliary lead main surface 410 has arectangular shape. Also, in the present embodiment, a first auxiliaryfront surface plating layer 411 is formed on the first auxiliary leadmain surface 410. The first auxiliary front surface plating layer 411 isinterposed between the first auxiliary lead 400 and the first wire 600.The first auxiliary front surface plating layer 411 is formed over theentire area of the first auxiliary lead main surface 410. The firstauxiliary front surface plating layer 411 is made of Ag of about 2 μm inthickness, for example. Note that, in FIG. 1, the first auxiliary frontsurface plating layer 411 is shaded for convenience of understanding.

The first auxiliary lead back surface 420 faces downward in the zdirection in the opposite direction to the first auxiliary lead mainsurface 410, and is used in order to surface mount the semiconductordevice 101. The first auxiliary lead back surface 420 has a rectangularshape. The first auxiliary lead back surface 420 overlaps with the firstauxiliary lead main surface 410 throughout its entirety and is containedwithin the first auxiliary lead main surface 410, as seen in the zdirection (in plan view). In the present embodiment, a first auxiliaryback surface plating layer 421 is formed on the first auxiliary lead400. The first auxiliary back surface plating layer 421 is laminated ona region of the first auxiliary lead 400 that is for forming the firstauxiliary lead back surface 420. In the present embodiment, the lowersurface of the first auxiliary back surface plating layer 421 in the zdirection is defined, for convenience, as the first auxiliary lead backsurface 420, although in a configuration that does not have firstauxiliary back surface plating layer 421, for example, the firstauxiliary lead back surface 420 may be constituted by the abovementionedportion made of Cu.

The first auxiliary full thickness part 430 is a region that extendsfrom the first auxiliary lead main surface 410 to the first auxiliarylead back surface 420 in the z direction. In the present embodiment, thefirst auxiliary full thickness part 430 indicates a region made of Cuexcluding the first auxiliary back surface plating layer 421.

The first auxiliary eave part 440 projects from a portion on the firstauxiliary lead main surface 410 side of the first auxiliary fullthickness part 430 in the x and y directions, which are at right anglesto the z direction. An upper end face of the first auxiliary eave part440 in the z direction is flush with the first auxiliary full thicknesspart 430. The first auxiliary eave part 440 constitutes the firstauxiliary lead main surface 410. In the present embodiment, the firstauxiliary eave part 440 has a first auxiliary front part 441, a firstauxiliary lateral part 442, and a first auxiliary rear part 443.

The first auxiliary front part 441 projects from the first auxiliaryfull thickness part 430 toward the main lead 300 in the x direction.

The first auxiliary lateral part 442 projects from the first auxiliaryfull thickness part 430 in the y direction. In the present embodiment,two first auxiliary lateral parts 442 are formed. The first auxiliarylateral part 442 that is located on the upper side in the y direction inFIG. 3 projects toward the second auxiliary lead 500. Also, in thepresent embodiment, the first auxiliary lead 400 has a first auxiliarylateral connecting part 451. The first auxiliary lateral connecting part451 projects from the first auxiliary eave part 440. The first auxiliarylateral connecting part 451 is formed to have the same thickness as thefirst auxiliary lateral parts 442. The direction in which the firstauxiliary lateral connecting part 451 projects is a direction that isorthogonal to a direction from the main lead 300 toward the firstauxiliary lead 400. The first auxiliary lateral connecting part 451 hasan end face that is exposed from the resin package 800. A distance L2(see FIG. 3) separating the first auxiliary lateral connecting part 451from the main lead 300 is 0.2 to 0.3 mm, for example.

The first auxiliary rear part 443 projects from the first auxiliary fullthickness part 430 in the opposite direction to the first auxiliaryfront part 441. In the present embodiment, the first auxiliary lead 400has a first auxiliary rear connecting part 452. The first auxiliary rearconnecting part 452 extends from the first auxiliary rear part 443 ofthe first auxiliary eave part 440, and is formed to have the samethickness as the first auxiliary rear part 443. An end face of the firstauxiliary rear connecting part 452 in the x direction is exposed fromthe resin package 800.

According to the abovementioned configuration, in the presentembodiment, all of the first auxiliary full thickness part 430 issurrounded by the first auxiliary eave part 440 as seen in the zdirection (in plan view). Also, upper surfaces of the first auxiliaryfull thickness part 430 and the first auxiliary eave part 440 in the zdirection form the first auxiliary lead main surface 410, and the firstauxiliary front surface plating layer 411 overlaps with all of the firstauxiliary full thickness part 430 and the first auxiliary eave part 440.

The second auxiliary lead 500 is disposed so as to be separated from themain lead 300 in the x direction at a position juxtaposed with the firstauxiliary lead 400 in the y direction. The second auxiliary lead 500 isexposed from the resin package 800 to the outside of the resin package800 as seen in the thickness direction z of the semiconductor element200. The second auxiliary lead 500 has a second auxiliary lead mainsurface 510, a second auxiliary lead back surface 520, a secondauxiliary full thickness part 530, and a second auxiliary eave part 540.The second auxiliary lead 500 is formed by performing patterning such asetching on a metal plate made of Cu, for example. The second auxiliarylead 500 is electrically connected to the semiconductor element 200.

The second auxiliary lead main surface 510 faces upward in the zdirection, and is the region to which the second wire 700 is bonded. Inthe present embodiment, the second auxiliary lead main surface 510 has arectangular shape. Also, in the present embodiment, a second auxiliarysurface plating layer 511 is formed on the second auxiliary lead mainsurface 510. The second auxiliary surface plating layer 511 isinterposed between the second auxiliary lead 500 and the second wire700. The second auxiliary surface plating layer 511 is formed over theentire area of the second auxiliary lead main surface 510. The secondauxiliary surface plating layer 511 is made of Ag of about 2 μm inthickness, for example. Note that, in FIG. 1, the second auxiliarysurface plating layer 511 is shaded for convenience of understanding.

The second auxiliary lead back surface 520 faces downward in the zdirection in the opposite direction to the second auxiliary lead mainsurface 510, and is used in order to surface mount the semiconductordevice 101. The second auxiliary lead back surface 520 has a rectangularshape. The second auxiliary lead back surface 520 overlaps with thesecond auxiliary lead main surface 510 throughout its entirety and iscontained within the second auxiliary lead main surface 510, as seen inthe z direction (in plan view). In the present embodiment, the secondauxiliary back surface plating layer 521 is formed on the secondauxiliary lead 500. The second auxiliary back surface plating layer 521is laminated on a region of the second auxiliary lead 500 that is forforming the second auxiliary lead back surface 520, and is made of Ni,Sn, or an alloy thereof. In the present embodiment, the lower surface ofthe second auxiliary back surface plating layer 521 in the z directionis defined, for convenience, as the second auxiliary lead back surface520, although in a configuration that does not have the second auxiliaryback surface plating layer 521, for example, the second auxiliary leadback surface 520 may be constituted by the abovementioned portion madeof Cu.

The second auxiliary full thickness part 530 is a region that extendsfrom the second auxiliary lead main surface 510 to the second auxiliarylead back surface 520 in the z direction. In the present embodiment, thesecond auxiliary full thickness part 530 indicates a region made of Cuexcluding the second auxiliary back surface plating layer 521.

The second auxiliary eave part 540 projects from a portion on the secondauxiliary lead main surface 510 side of the second auxiliary fullthickness part 530 in the x and y directions, which are at right anglesto the z direction. An upper end face of the second auxiliary eave part540 in the z direction is flush with the second auxiliary full thicknesspart 530. The second auxiliary eave part 540 constitutes the secondauxiliary lead main surface 510. In the present embodiment, the secondauxiliary eave part 540 has a second auxiliary front part 541, a secondauxiliary lateral part 542, and a second auxiliary rear part 543. Thethickness of the second auxiliary eave part 540 is half of the secondauxiliary full thickness part 530, for example.

The second auxiliary front part 541 projects from the second auxiliaryfull thickness part 530 toward the main lead 300 in the x direction.

The second auxiliary lateral part 542 projects from the second auxiliaryfull thickness part 530 in the y direction. In the present embodiment,two second auxiliary lateral parts 542 are formed. The second auxiliarylateral part 542 that is located on the lower side in the y direction inFIG. 3 projects toward the first auxiliary lead 400. Also, in thepresent embodiment, the second auxiliary lead 500 has a second auxiliarylateral connecting part 551. The second auxiliary lateral connectingpart 551 projects from the second auxiliary eave part 540. The secondauxiliary lateral connecting part 551 is formed to have the samethickness as the second auxiliary lateral parts 542. The direction inwhich the second auxiliary lateral connecting part 551 projects is adirection that is orthogonal to a direction from the main lead 300toward the second auxiliary lead 500. The second auxiliary lateralconnecting part 551 has an end face that is exposed from the resinpackage 800. A distance L3 (see FIG. 3) separating the second auxiliarylateral connecting part 551 from the main lead 300 is 0.2 to 0.3 mm, forexample.

The second auxiliary rear part 543 projects from the second auxiliaryfull thickness part 530 in the opposite direction to the secondauxiliary front part 541. In the present embodiment, the secondauxiliary lead 500 has a second auxiliary rear connecting part 552. Thesecond auxiliary rear connecting part 552 extends from the secondauxiliary rear part 543 of the second auxiliary eave part 540, and isformed to have the same thickness as the second auxiliary rear part 543.An end face of the second auxiliary rear connecting part 552 in the xdirection is exposed from the resin package 800.

According to the abovementioned configuration, in the presentembodiment, all of the second auxiliary full thickness part 530 issurrounded by the second auxiliary eave part 540 as seen in the zdirection (in plan view). Also, upper surfaces of the second auxiliaryfull thickness part 530 and the second auxiliary eave part 540 in the zdirection form the second auxiliary lead main surface 510, and thesecond auxiliary surface plating layer 511 overlaps with all of thesecond auxiliary full thickness part 530 and the second auxiliary eavepart 540.

The first wire 600 is joined to the first front surface electrode 211 ofthe semiconductor element 200 and the first auxiliary lead main surface410 of the first auxiliary lead 400, and has a first bonding part 610and a second bonding part 620. The first wire 600 is made of Au of about20 μm in diameter.

The first bonding part 610 is joined to the first auxiliary lead mainsurface 410 of the first auxiliary lead 400, and has a coronal lumpportion. The second bonding part 620 is joined to the first frontsurface electrode 211 of the semiconductor element 200 via a first bump630. The second bonding part 620 has a tapered shape whose thickness inthe z direction decreases toward the tip. The first bump 630 is a regionsimilar to the lump portion of the first bonding part 610. In thepresent embodiment, the first bump 630 has slightly less volume than thelump portion of the first bonding part 610. Note that the second bondingpart 620 is shown in FIG. 11.

The second wire 700 is joined to the second front surface electrode 212of the semiconductor element 200 and the second auxiliary lead mainsurface 510 of the second auxiliary lead 500, and has a first bondingpart 710 and a second bonding part 720. The second wire 700 is made ofAu of about 20 μm in diameter.

The first bonding part 710 is joined to the second auxiliary lead mainsurface 510 of the second auxiliary lead 500, and has a coronal lumpportion. The second bonding part 720 is joined to the second frontsurface electrode 212 of the semiconductor element 200 via a second bump730. The second bonding part 720 has a tapered shape whose thickness inthe z direction decreases toward the tip. The second bump 730 is aregion similar to the lump portion of the first bonding part 710. In thepresent embodiment, the second bump 730 has slightly less volume thanthe lump portion of the first bonding part 710.

The resin package 800 covers the semiconductor element 200, and aportion of each of the main lead 300, the first auxiliary lead 400 andthe second auxiliary lead 500, and is made of a black epoxy resin, forexample. Also, the resin package 800 exposes each of the back surface320 of the main lead 300, the first auxiliary lead back surface 420 ofthe first auxiliary lead 400 and the second auxiliary lead back surface520 of the second auxiliary lead 500 on the lower side in the zdirection. Also, in the present embodiment, a distance from upper endsof the first wire 600 and the second wire 700 in the z direction to anupper end of the resin package 800 in the z direction is about 50 μm.

Next, the operation and effects of the present embodiment will bedescribed. In the present embodiment, the notch 380 is formed in themain lead 300. The notch 380 has a shape that is recessed toward thecenter of the main lead 300 as seen in the thickness direction z of thesemiconductor element 200. As a result of such a configuration, the areaof the main lead main surface 310 of the main lead 300 can be reduced,thus enabling the location where the semiconductor element 200 is to bedisposed on the main lead 300 to be defined. Even in the case where thesemiconductor element 200 is comparatively small, the semiconductorelement 200 can thereby be disposed at a desired location on the mainlead 300, irrespective of the technician.

When manufacturing the semiconductor device 101, the semiconductorelement 200 is die bonded to the main lead 300 at a high temperature(e.g., about 400° C.), and the semiconductor element 200 and the mainlead 300 are then cooled to room temperature. The semiconductor element200 and the main lead 300 have different coefficients of thermalexpansion. Thus, when the semiconductor element 200 and the main lead300 are cooled, the semiconductor element 200 and the main lead 300contract at different rates. As a result, when the semiconductor element200 and the main lead 300 are cooled, the semiconductor element 200could possibly be damaged, due to the semiconductor element 200 beingsubject to excessive stress load. In particular, the main eave part 340is easily deformed as compared with the main full thickness part 330. Inthe present embodiment, as described above, the semiconductor element200 can be disposed in substantially the same position on the main lead300 irrespective of the technician, thus enabling the semiconductorelement 200 to be disposed on the main lead 300, so that as much of thesemiconductor element 200 as possible overlaps with the main fullthickness part 330. Damage to the semiconductor element 200 caused bythe difference in thermal contraction between the semiconductor element200 and the main lead 300 can thereby be prevented.

According to the present embodiment, the main lead main surface 310 andthe semiconductor element 200 overlap with each of the main fullthickness part 330 and the main eave part 340 as seen in the z direction(in plan view). The main eave part 340 exhibits a function of enhancingthe joining strength between the main lead 300 and the resin package800. The main lead 300 can be inhibited from protruding excessively fromthe semiconductor element 200, while achieving an improvement in thisjoining strength. This contributes to reducing the dimensions of thesemiconductor device 101 as seen in the z direction (in plan view).

As a result of the main eave part 340 having the main front part 341,the joining strength between the main lead 300 and the resin package 800can be enhanced. Also, the main lead back surface 320 excessivelyapproaching the first auxiliary lead back surface 420 and the secondauxiliary lead back surface 520 can be avoided, while bringing thesemiconductor element 200 closer to the first auxiliary lead 400 and thesecond auxiliary lead 500.

As a result of the main eave part 340 having the main lateral parts 342and the main rear part 343, the joining strength between the main lead300 and the resin package 800 can be enhanced. A configuration in whichall of the main full thickness part 330 is surrounded by the main eavepart 340 is favorable for enhancing the joining strength between themain lead 300 and the resin package 800.

The first main lateral connecting parts 351A, the second main lateralconnecting parts 351B and the main rear connecting parts 352appropriately hold the main lead 300 in the manufacturing process of thesemiconductor device 101. The end faces of the first main lateralconnecting parts 351A, the second main lateral connecting parts 351B andthe main rear connecting parts 352 are separated from the main lead backsurface 320 that is exposed from the resin package 800. There is thuslittle possibility of solder for surface mounting of the semiconductordevice 101 accidentally spreading to the end faces of the first mainlateral connecting parts 351A, the second main lateral connecting parts351B, and the main rear connecting parts 352.

As a result of the main front surface plating layer 311 being formed onthe main lead main surface 310, the joining strength between the backsurface electrode 220 of the semiconductor element 200 and the main leadmain surface 310 can be enhanced. As a result of the main front surfaceplating layer 311 overlapping with all of the main eave part 340, thearea that can be utilized as the main lead main surface 310 can beenlarged.

As a result of the first auxiliary lead 400 having the first auxiliaryeave part 440, the joining strength between the first auxiliary lead 400and the resin package 800 can be enhanced. As a result of the firstauxiliary eave part 440 having the first auxiliary front part 441, thefirst auxiliary lead back surface 420 excessively approaching the mainlead back surface 320 can be avoided while enhancing the joiningstrength with the resin package 800.

As a result of the first auxiliary eave part 440 having the firstauxiliary lateral parts 442 and the first auxiliary rear part 443, thejoining strength between the first auxiliary lead 400 and the resinpackage 800 can be enhanced. A configuration in which all of the firstauxiliary full thickness part 430 is surrounded by the first auxiliaryeave part 440 is favorable for enhancing the joining strength betweenthe first auxiliary lead 400 and the resin package 800. As a result ofthe first auxiliary lateral part 442 on the second auxiliary lead 500side being relatively large, the first auxiliary lead back surface 420excessively approaching the second auxiliary lead back surface 520 canbe avoided, together with achieving an improvement in joining strength.

The first auxiliary lateral connecting part 451 and the first auxiliaryrear connecting part 452 appropriately hold the first auxiliary lead 400in the manufacturing process of the semiconductor device 101. An endface of the first auxiliary lateral connecting part 451 in the ydirection and an end face of the first auxiliary rear connecting part452 in the x direction are separated from the first auxiliary lead backsurface 420 that is exposed from the resin package 800. There is thuslittle possibility of solder for surface mounting the semiconductordevice 101 accidentally spreading to the end face of the first auxiliarylateral connecting part 451 in the y direction and the end face of thefirst auxiliary rear connecting part 452 in the x direction.

As a result of the first auxiliary front surface plating layer 411 beingformed on the first auxiliary lead main surface 410, the joiningstrength between the first wire 600 and the first auxiliary lead mainsurface 410 can be enhanced.

As a result of the second auxiliary lead 500 having the second auxiliaryeave part 540, the joining strength between the second auxiliary lead500 and the resin package 800 can be enhanced. As a result of the secondauxiliary eave part 540 having the second auxiliary front part 541, thesecond auxiliary lead back surface 520 excessively approaching the mainlead back surface 320 can be avoided, while enhancing the joiningstrength with the resin package 800.

As a result of the second auxiliary eave part 540 having the secondauxiliary lateral parts 542 and the second auxiliary rear part 543, thejoining strength between the second auxiliary lead 500 and the resinpackage 800 can be enhanced. A configuration in which all of the secondauxiliary full thickness part 530 is surrounded by the second auxiliaryeave part 540 is favorable for enhancing the joining strength betweenthe second auxiliary lead 500 and the resin package 800. As a result ofthe second auxiliary lateral part 542 on the first auxiliary lead 400side being relatively large, the second auxiliary lead back surface 520excessively approaching the first auxiliary lead back surface 420 can beavoided, together with achieving an improvement in joining strength.

The second auxiliary lateral connecting part 551 and the secondauxiliary rear connecting part 552 appropriately hold the secondauxiliary lead 500 in the manufacturing process of the semiconductordevice 101. An end face of the second auxiliary lateral connecting part551 in the y direction and an end face of the second auxiliary rearconnecting part 552 in the x direction are separated from the secondauxiliary lead back surface 520 that is exposed from the resin package800. There is thus little possibility of solder for surface mounting thesemiconductor device 101 accidentally spreading to the end face of thesecond auxiliary lateral connecting part 551 in the y direction and theend face of the second auxiliary rear connecting part 552 in the xdirection.

As a result of the second auxiliary surface plating layer 511 beingformed on the second auxiliary lead main surface 510, the joiningstrength between the second wire 700 and the second auxiliary lead mainsurface 510 can be enhanced.

With the join between the semiconductor element 200 and the main leadmain surface 310 of the main lead 300, the back surface electrode 220consisting of a monolithic metal layer is joined directly to the mainlead main surface 310, and vibration is not applied at the time ofjoining. As a result of such a configuration, a margin that allows forvibration does not need to be set in the region of the main lead 300that is located around the semiconductor element 200. This isadvantageous for miniaturization of the semiconductor device 101.

Note that, in practice, when the main lead 300, the first auxiliary lead400 and the second auxiliary lead 500 are patterned by etching, theboundary between the main full thickness part 330 and the main eave part340 could be a curved surface, rather than the definite angle showed inFIGS. 1 to 9 and the like being formed. Similarly, other boundaries suchas between the first auxiliary full thickness part 430 and the firstauxiliary eave part 440 of the first auxiliary lead 400 could be curvedsurfaces. This is because even if a design intended to obtain the formshown in FIGS. 1 to 9 and the like is achieved, the curved surfacesdescribed above may unavoidably occur in the etching process, in thecase where the semiconductor device 101 has the extremely compactconfiguration described above.

FIGS. 12 and 13 show an example of a semiconductor device that is basedon a second embodiment of the present invention. A semiconductor device102 of the present embodiment differs from the abovementioned embodimentin that the notch 380 is provided in a different location.

FIG. 12 is a perspective view showing the semiconductor device 102. FIG.13 is a plan view showing the semiconductor device 102.

In the present embodiment, the notch 380 has a shape that is recessedfrom a region of the main lead 300 on the opposite side to the firstauxiliary lead 400, as seen in the z direction (in plan view). Also, themain lead 300 has an end face 391 that is located on the opposite sideto the first auxiliary lead 400. The notch 380 has a shape that isrecessed from the end face 391 as seen in the z direction (in planview). The notch 380 similarly has a shape in which the main frontsurface plating layer 311 is recessed in the present embodiment. Notethat the main rear connecting parts 352 project rearward from an endface 391.

Such an embodiment similarly enables the semiconductor element 200 to bedisposed at a desired location on the main lead 300, irrespective of thetechnician, even in the case where the semiconductor element 200 iscomparatively small.

The present invention is not limited to the abovementioned embodiments.Various design modifications can be made to the specific configurationsof the respective parts of the present invention.

1. A semiconductor device comprising: a semiconductor element; a mainlead on which the semiconductor element is disposed; and a resin packagecovering the semiconductor element and the main lead, wherein the mainlead is formed with a notch recessed toward a center of the main lead inplan view as seen in a thickness direction of the semiconductor element.2. The semiconductor device according to claim 1, further comprising afirst auxiliary lead electrically connected to the semiconductorelement, wherein the first auxiliary lead is separated from the mainlead and exposed from the resin package.
 3. The semiconductor deviceaccording to claim 2, wherein the notch has a shape recessed in adirection from the first auxiliary lead toward the main lead in planview.
 4. The semiconductor device according to claim 2, wherein the mainlead has an end face located furthest on the first auxiliary lead sideof the main lead, and the notch has a shape recessed from the end facein plan view.
 5. The semiconductor device according to claim 2, whereinthe notch has a shape recessed from a region on an opposite side of themain lead to the first auxiliary lead in plan view.
 6. The semiconductordevice according to claim 5, wherein the main lead has an end facelocated on the opposite side of the main lead to the first auxiliarylead, and the notch has a shape recessed from the end face in plan view.7. The semiconductor device according to claim 2, wherein the main leadhas a main lead main surface and a main lead back surface that face inopposite directions to each other, and the semiconductor element isdisposed on the main lead main surface.
 8. The semiconductor deviceaccording to claim 7, wherein the main lead includes a main fullthickness part and a main eave part, the main full thickness partextends from the main lead main surface to the main lead back surface,and the main eave part projects from the main full thickness part in adirection at right angles to the thickness direction of thesemiconductor element.
 9. The semiconductor device according to claim 8,wherein the semiconductor element overlaps with each of the main fullthickness part and the main eave part in plan view.
 10. Thesemiconductor device according to claim 8, wherein the notch is formedin the main eave part.
 11. The semiconductor device according to claim1, wherein the semiconductor element overlaps with the main lead in planview, throughout an entirety of the semiconductor element.
 12. Thesemiconductor device according to claim 8, wherein the main eave parthas a main front part, the main front part projects from the main fullthickness part toward the first auxiliary lead, and the notch is formedin the main front part.
 13. The semiconductor device according to claim12, wherein the main eave part has a main lateral part, and the mainlateral part projects from the main full thickness part in a directionat right angles to the direction in which the main front part projects.14. The semiconductor device according to claim 8, wherein the main leadincludes a first main lateral connecting part projecting from the maineave part, the direction in which the first main lateral connecting partprojects is a direction orthogonal to a direction from the main leadtoward the first auxiliary lead, and the first main lateral connectingpart has an end face exposed from the resin package.
 15. Thesemiconductor device according to claim 14, wherein the main leadincludes a second main lateral connecting part projecting from the maineave part, the direction in which the second main lateral connectingpart projects is a direction orthogonal to a direction from the mainlead toward the first auxiliary lead, the second main lateral connectingpart has an end face exposed from the resin package, and the first mainlateral connecting part and the second main lateral connecting part arejuxtaposed with each other.
 16. The semiconductor device according toclaim 15, wherein the second main lateral connecting part is locatedbetween the first main lateral connecting part and the first auxiliarylead in a direction from the main lead toward the first auxiliary lead.17. The semiconductor device according to claim 15, wherein a distanceseparating the first main lateral connecting part from the second mainlateral connecting part is 0.2 to 0.3 mm.
 18. The semiconductor deviceaccording to claim 12, wherein the main eave part has a main rear part,and the main rear part projects from the main full thickness part in anopposite direction to the direction in which the main front partprojects.
 19. The semiconductor device according to claim 18, whereinthe main lead includes a main rear connecting part projecting from themain rear part, and the main rear connecting part has an end faceexposed from the resin package.
 20. The semiconductor device accordingto claim 8, wherein the main full thickness part is surrounded by themain eave part in plan view, throughout an entirety thereof.
 21. Thesemiconductor device according to claim 8, further comprising a mainfront surface plating layer formed on the main lead, and interposedbetween the semiconductor element and the main lead.
 22. Thesemiconductor device according to claim 21, wherein the main frontsurface plating layer has a substantially rectangular shape in planview.
 23. The semiconductor device according to claim 21, wherein thenotch has a shape in which the main front surface plating layer isrecessed in plan view.
 24. The semiconductor device according to claim21, wherein the main front surface plating layer overlaps with anentirety of the main eave part.
 25. The semiconductor device accordingto claim 2, wherein the first auxiliary lead includes a first auxiliaryfull thickness part and a first auxiliary eave part, the first auxiliarylead has a first auxiliary lead main surface and a first auxiliary leadback surface that face in opposite directions to each other, the firstauxiliary full thickness part extends from the first auxiliary lead mainsurface to the first auxiliary lead back surface, and the firstauxiliary eave part projects from the first auxiliary full thicknesspart in a direction at right angles to the thickness direction of thesemiconductor element, and constitutes the first auxiliary lead mainsurface.
 26. The semiconductor device according to claim 25, wherein thefirst auxiliary eave part has a first auxiliary front part, and thefirst auxiliary front part projects from the first auxiliary fullthickness part toward the main lead.
 27. The semiconductor deviceaccording to claim 25, wherein the first auxiliary lead includes a firstauxiliary lateral connecting part projecting from the first auxiliaryeave part, the direction in which the first auxiliary lateral connectingpart projects is a direction orthogonal to a direction from the mainlead toward the first auxiliary lead, and the first auxiliary lateralconnecting part has an end face exposed from the resin package.
 28. Thesemiconductor device according to claim 27, wherein a distanceseparating the first auxiliary lateral connecting part from the mainlead is 0.2 to 0.3 mm.
 29. The semiconductor device according to claim2, further comprising a first wire joined to the semiconductor element,and electrically connecting the semiconductor element and the firstauxiliary lead.
 30. The semiconductor device according to claim 29,further comprising a first auxiliary surface plating layer interposedbetween the first auxiliary lead and the first wire.
 31. Thesemiconductor device according to claim 2, further comprising a secondauxiliary lead that is electrically connected to the semiconductorelement, wherein the second auxiliary lead is separated from the mainlead and exposed from the resin package.
 32. The semiconductor deviceaccording to claim 31, further comprising a second wire joined to thesemiconductor element, and electrically connecting the semiconductorelement and the second auxiliary lead.
 33. The semiconductor deviceaccording to claim 32, further comprising a second auxiliary surfaceplating layer interposed between the second auxiliary lead and thesecond wire.
 34. The semiconductor device according to claim 1, whereinthe semiconductor element has a semiconductor layer, a eutectic layer ofa semiconductor and a metal, and a monolithic metal layer constituting aback surface electrode that are laminated one on the other, and themonolithic metal layer is joined directly to the main lead.
 35. Thesemiconductor device according to claim 34, wherein the eutectic layeris made of a eutectic of Si and Au.
 36. The semiconductor deviceaccording to claim 34, wherein the monolithic metal layer is thinnerthan the eutectic layer.